While the building and printing industries flourished in pre-Civil War Columbus, manufacturing languished. The manufacturing base grew and diversified from 1820 to 1850. Few unions emerged, and those that did seldom lasted long. During the Civil War business and manufacturing increased to serve the camps and prisons established in Columbus. When the war ended, Columbus's workers launched the first concerted effort to build a labor movement. In August 1869 the arrival of the first train of the Hocking Valley Railroad introduced a new chapter in the city's industrial history. By World War I, industry had migrated out of the downtown area. Workers were excluded from a major say in city affairs, confined to overcrowded and inadequately served neighborhoods, and trapped in low-paying, dirty, demanding jobs. The characteristic pattern of the labor movement until the 1930s emerged: workers unionized during prosperity and retreated with recessions. World War I stimulated the economy; peace brought a depression. But because of the city's diverse economic base, it did not feel the depression as severely as other locations; nor did it experience the prosperity of the 1920s to the same degree as other communities; hence, increasingly, the word "moderate" described all national trends as they applied to Columbus. World War II had the greatest impact upon Columbus's labor movement. Public employment doubled, and the manufacturing sector expanded dramatically. Curtiss-Wright's air force factory work force was unionized shortly after it began production in 1941. For the past 2 decades, the challenge for organized labor in central Ohio has been to launch new initiatives in the face of a dramatically changing social and economic environment. (Contains 27 related readings.) (YLB)